Bertram31.com General Bulletin Board

Re: Radio Shack Multimeter

Posted By: Vic Roy
Date: Monday, 2 May 2005, at 7:51 p.m.

In Response To: Radio Shack Multimeter *LINK* *PIC* (STeveZ)

Steve - a fully charged 12v battery will read about 12.8 volts, and when a good charger or the engine alternator is on it, should show about 13.6 to 14 volts. When you set the range on your new voltmeter, you always need to guess what you are going to see to keep from over ranging it. Let's walk you thru it. Go get a flashlight battery, which produces about 1.5 volts. Set your meter on DC and the 2 volt range. Put the red meter probe on the end of the battery with the dimple on it and the black lead on the other (flat side) and read the meter. You should see about 1.5 - 1.6 volts and some decimals. Now reverse the leads and you will see the same voltage, but a minus sign on the left side of the meter, indicating you have the leads reversed. Do this a couple of times to get familiar with the polarity reading. Now jump the range up to 20 volts and do the same thing, and you should see the same voltage with less digits. You get the pix.

Now, let's do some resistance testing, using the ohmeter function. All this does is use the little battery in the meter to run some current, DC, from the red thru the device being tested and back thru the black. If there is a solid wire between the two leads, or you touch the leads together, there will be near zero resistance, or zero ohms resistance, since resistance is measured in ohms. Unless you are doing complex electronics work, the use of this function is to see if a circuit passes current, not how much. Imagine a fuse or a light bulb. If you have the meter set to ohms and touch a lead to each end of the fuse and the meter says "overload" then the fuze is blown, because it's telling you no current is going thru the fuze back to the meter. If the meter says a number, then the fuze is not blown. Same for a light bulb - if you touch a lead to the center and the other to the outside of the base and get "overload", the bulb is burnt out. All the ohms funtion is telling you is that current will pass between the two lead ends, thus whatever is between them (fuze, light bulb) is carrying current, so is good.

Try this and we'll take it up from there.

UV

Messages In This Thread

Test meters
bruce -- Monday, 2 May 2005, at 5:41 p.m.

Re: Test meters
Rawleigh -- Monday, 2 May 2005, at 6:40 p.m.

Re: Test meters
bruce -- Monday, 2 May 2005, at 6:45 p.m.

Re: Test meters
Vic Roy -- Monday, 2 May 2005, at 6:43 p.m.

Re: Test meters
cwj -- Monday, 2 May 2005, at 9:20 p.m.

Re: Test meters
Vic Roy -- Monday, 2 May 2005, at 10:57 p.m.

Radio Shack Multimeter *LINK* *PIC*
STeveZ -- Monday, 2 May 2005, at 7:24 p.m.

Re: Radio Shack Multimeter
Vic Roy -- Monday, 2 May 2005, at 7:51 p.m.

Re: Radio Shack Multimeter
John F. -- Monday, 2 May 2005, at 8:43 p.m.